Absolute Value and Inequalities: Exploring Distance and Tolerance
Understand absolute value concepts and how to solve equations and inequalities related to distance and tolerance. Explore real number properties and practical examples.
Absolute Value and Inequalities: Exploring Distance and Tolerance
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Presentation Transcript
Chapter 1.8 Absolute Value and Inequalities
Recall from Chapter R that the absolute value of a number a, written |a|, gives the distance from a to 0 on a number line. By this definition, the equation |x| = 3 can be solved by finding all real numbers at a distance of 3 units from 0.
|x| = 3 Two numbers satisfy this equation, 3 and -3, so the solution set is {-3, 3}. Distance is 3. Distance is 3. Distance is greater than 3. Distance is less than 3. Distance is greater than 3. | | | 3 -3 0
Similarly |x| < 3 is satisfied by all real numbers whose distances from 0 are less than 3, that is, the interval -3<x<3 or (-3,3).
Example 3 Solving Absolute Value Inequalities Requiring a Transformation
Absolute Value Models for Distance and Tolerance Recall from Selection R.2 that is a and b represent two real numbers, then the absolute value of their difference, either |a - b| or |b – a|, represent the distance between them. This fact is used to write absolute value equations or inequalities to express distance.
Example 5 Using Absolute Value Inequaliteis to Describe Distances Write each statement using an absolute value inequality. (a) k is no less than 5 units from 8
Example 5 Using Absolute Value Inequaliteis to Describe Distances Write each statement using an absolute value inequality. (b) n is within .001 unit of 6
Example 6 Using Absolute Value to Model Tolerance Suppose y = 2x + 1 and we want y to be within .01 unit of 4. For what values of x will this be true? |y – 4| < .01 |2x + 1 – 4| < .01
Homework Section 1.8 # 1 - 82